import 'dart:async';

import 'package:flutter/material.dart';

class Swiper extends StatefulWidget {
  final double width;
  final double height;
  final List<String> list;
  const Swiper({
    super.key,
    this.width = double.infinity,
    this.height = 200,
    required this.list,
  });

  @override
  State<Swiper> createState() => _SwiperState();
}

class _SwiperState extends State<Swiper> {
  int _currentIndex = 0;
  List<Widget> pageList = [];
  late PageController _pageController;
  late Timer timer;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    for (var i = 0; i < widget.list.length; i++) {
      pageList.add(
        ImagePage(
          src: widget.list[i],
          width: widget.width,
          height: widget.height,
        ),
      );
    }

    _pageController = PageController(initialPage: 0);
    timer = Timer.periodic(const Duration(seconds: 3), (t) {
      _pageController.animateToPage(
        (_currentIndex + 1) % pageList.length,
        duration: const Duration(milliseconds: 200),
        curve: Curves.linear,
      ); // 跳转的动画
    });
  }

  @override
  void dispose() {
    super.dispose();
    timer.cancel();
    _pageController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        SizedBox(
          height: 200,
          child: PageView.builder(
            controller: _pageController,
            onPageChanged: (index) {
              setState(() {
                _currentIndex = index % widget.list.length;
              });
            },
            itemBuilder: (context, index) {
              return pageList[index % widget.list.length];
            },
          ),
        ),
        Positioned(
          left: 0,
          right: 0, // 设置left 0，right 0 就会占满整行
          bottom: 2,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: List.generate(widget.list.length, (index) {
              return Container(
                margin: const EdgeInsets.all(5),
                width: 10,
                height: 10,
                decoration: BoxDecoration(
                  color: _currentIndex == index ? Colors.white : Colors.grey,
                  shape: BoxShape.circle,
                ),
              );
            }).toList(),
          ),
        ),
      ],
    );
  }
}

class ImagePage extends StatelessWidget {
  final double width;
  final double height;
  final String src;
  const ImagePage({
    super.key,
    this.width = double.infinity,
    this.height = 200,
    required this.src,
  });

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: width,
      height: height,
      child: Image.network(src, fit: BoxFit.cover),
    );
  }
}
